The potential of gamma-ray bursts (GRBs) to act as high redshift
probes has been recognized since they were first unveiled at
cosmological distances more than a decade ago. Since this time we
have used them to locate star forming galaxies at progressively
higher redshift, culimating in the discovery of GRB 090423 at a
spectroscopically confirmed redshift of 8.2 last year, with a further
burst now possible at z~9. I will present the discovery of these
high redshift GRBs, the study of their host galaxies with the
refurbished Hubble Space Telescope, and the implications they have
for star formation in the early Universe.